Clayton Lockett's execution, scheduled for Thursday, was postponed Tuesday until April 22 because Oklahoma does not have all of the lethal drugs necessary to carry out the lethal injection. / AP

by Gregg Zoroya, USA TODAY

by Gregg Zoroya, USA TODAY

An appeals court in Oklahoma on Tuesday postponed the execution of a convicted murderer slated for Thursday because the state has run out of lethal injection drugs. A second prisoner's death sentence slated for next week was also delayed.

The case is the latest in a growing controversy nationwide over the use of lethal injection for executions. Sources for the necessary drugs have dried up, and states with death penalties are scrambling to find more.

Convicted killer Clayton Lockett was slated to be executed Thursday by lethal injection and a second Oklahoma inmate, Charles Warner, was to die March 27. Lockett's execution was postponed until April 22 and Warner's to April 29.

Lockett is awaiting execution for his role in the shooting death of a 19-yer-old woman in 1999. Warren is on death row for murdering his girlfriend's 11-month-old daughter in 1997.

Lawyers for both men asked judges to postpone the executions because it was unclear how they would be carried out.

The state attorney general's office conceded in court documents Monday that state executioners have run out of pentobarbital, a necessary barbiturate used in the execution process. The state lawyers may have to find another combination of drugs to carry out the executions.

"This (search) has been nothing short of a Herculean effort," Assistant Attorney General Seth Branham wrote in papers filed Monday.

Four members of the five-judge appellate panel on Tuesday ordered that both executions be delayed.

"This court (has) no confidence that the state will be able to procure the necessary drugs before the scheduled executions are to be carried out," the ruling said.

Manufacturers are cutting off supplies of lethal injections, in many cases because they are located in European countries that oppose the death penalty. Prison officials in death penalty states have had to improvise, trading drugs with one another or turning to small pharmacies that will manufacture drugs to order.

The struggle to procure pharmaceuticals plays out as executions appear to be on the decline. Although a majority of states -- 32-- still have the death penalty, the number of executions has fallen from 98 in 1999 to 39 last year.

In recent years, New York, New Jersey, New Mexico, Illinois, Connecticut and Maryland have abolished the death sentence; and governors in Washington, Colorado and Oregon have suspended the punishment. Courts have halted executions in Georgia, Arkansas, Tennessee and Louisiana over lethal injection issues.

Like many states that turned to this method in recent decades -- rejecting age-old methods such as electrocution, gas chamber or firing squad -- Oklahoma state officials use a three-drug protocol. They first anesthetize the condemned with a barbiturate such as pentobarbital, then paralyze them with vecuronium bromide and stop their hearts with potassium chloride.

Pentobarbital has become increasingly difficult for states to acquire, as has vecuronium bromide.

Condemned prisoners have flooded courts with lawsuits, arguing that chemicals made by so-called compounding pharmacies may be impure and ultimately cause them to suffer during the execution process.

They've demanded to know which pharmacies produce the drugs. But states such as Oklahoma, Texas and Missouri have refused to disclose their drug sources because these local pharmacies tend to refuse to do business with them once they are publicly linked to executions.

In court documents he filed Monday, Branham told the appeals court that prison officials thought they had a deal to buy drugs from a pharmacy last Wednesday. But the opportunity fell through.